The meteor strike that injured hundreds of people in Russia earlier this year could have been much more dangerous according to new research, and scientists say it "shows that the Earth is vulnerable".

The violent explosion on February 18 saw the 20-metre space rock split into fragments miles above the city of Chelyabinsk and was the biggest blast of its kind in more than 100 years.

It briefly outshone the sun and inflicted severe burns on observers below, as well as smashing windows and rattling buildings.

But researchers say a more solid rock would have caused greater damage and casualties.

Workers examine damage to buildings in Chelyabinsk

One report author Victor Grokhovsky told Sky News: "The unusual thing about this asteroid is that it was very loose in nature. It was more like a clump of gravel pressed together.

"It was flying in space for a long time, got into the atmosphere and was split up into fragments there. This happened very high up and most of it vaporised before it got to Earth - less than 1% of fragments reached the Earth."

He added: "These kinds of events will continue happening, the question is how frequently and how dangerous it would be.

A piece of the meteorite is recovered from the Chebarkul Lake

"If this meteorite was more sturdy, it could do more damage. But meteors of this size are not studied at all, we don't even have equipment for that at present."

For the first time ever in history the fall of the meteor occurred over an heavily populated area. While that led to many injuries, it also armed researchers with a large number of video records and eyewitness accounts.

This allowed a team of field researchers to determine the trajectory and impact area with precision.

A meteorite contrail is seen over a vilage of Bolshoe Sidelnikovo

"This was a very visible event, it did not occur over Siberian forests but it was viewed in many populated regions and it showed that the Earth is vulnerable," said Mr Grokhovsky.

"It gave us great material for researchers because we had access to very fresh samples - we had samples in our labs within two days."

The team also visited 50 villages to verify the extent of the damage. The pressure from the shockwave caused a complex pattern of destruction.

Nearly half the buildings in Chelyabinsk had shattered glass. Suspended ceilings were sucked down. There were nearly 1,700 injuries, including cuts from glass, concussion, retinal burns and sunburn.

A victim of the meteor shower, Katya Smolina, told Sky News: "I was thrown back by the pressure wave when trying to leave my school building and a glass door came down behind me, lodging a shard of glass into my leg.

"It was very scary people panicked and there was a lot of blood."

A still of a meteor streaking across the sky in Russia

The meteor was at its brightest and hottest when it was 18 miles above the Earth. Its speed at this point has been calculated at 40,000mph, or 11.6 miles per second.

That means a rock that was initially the size of a double-decker bus was travelling at 20 times the speed of a bullet.

It was the largest object to hit Earth since the Tunguska event of 1908, when an exploding comet or asteroid destroyed 2,000 square kilometers of Siberian forest.